RWB he looked very comfortable in but what happens the day Wenger decides 343 isn't working for us so RWB no longer exists? We go back to Ox being a sub-par right winger? An average central midfielder? And even if we stick with 343, is he really going to displace Bellerin for an entire season? And the papers are trying to make out he doesn't even want to be a RWB.
In my head at least this is a player that's something like 4th choice CM, 2nd/3rd choice RW and 2nd choice RWB (I thought he did better than Bellerin but I think Bellerin seemed like he wasn't 100%) so there's no reason to fight to hold onto a squad player like that if there's cash banging on the door and the potential to bring in an improvement to any of those positions he can play.
The only thing that's turned me a bit towards him is he seemed to be one of the few showing real heart last season but I've seen that come and go in so many players before that I don't trust it. He did look basically depressed on the pitch the year before after all.
While I'll admit there's the potential for him to maybe become a useful player to have around, I still believe we're more likely to regret giving him 5 years of a very good salary than taking a chunk of money for him and moving on to someone else.